Bro... do you think it's from the cycle (aka "test flu") or just seasonal?
I ALWAYS get "test flu" usually by the end of the first week or so...same symptoms as your typical flu.... it lasts 2-3 days at most then good to go.
Listen, don't stress about losing a few days (yah, I know..it SOUNDS easy)... your body will bounce back with lightening speed, guaranteed....muscle memory is a beautiful thing... if you've ever taken a week or longer off from the gym and then started up again, you'll definitely know what I'm talking about.
Definitely drink tons of water... take your mutli's, Vitamin C & Zinc especially... get as many nutrients as you can to help your body recover faster (eat clean!)...and you'll good to go in no time!